The Nuss procedure was introduced in 1987 for the correction of pectus excavatum. In this procedure, a stainless steel bar is placed underneath the sternum. To report cutaneous reactions associated with Nuss bar placement. Over a period of 30 months, 50 patients underwent the Nuss procedure. The study population was limited to those who developed clinically significant cutaneous reactions postoperatively. Patient information was obtained from electronic medical records. All patients had been patch tested preoperatively with stainless steel discs supplied by the bar manufacturer. When performed, expanded patch testing was carried out in accordance with the North American Contact Dermatitis Group guidelines. Postoperatively, 3 patients developed areas of protuberant granulation tissue at one or more incision sites. One patient developed localized oedema, dermatitis, and lymphadenopathy. Two of these 4 patients underwent further patch testing. Of these 2, 1 with dermatitis had a positive reaction to nickel and the other, with granulation tissue, tested negative for metal allergy. Despite clinical evidence of cutaneous reactions or putative allergy, no patient required early removal of the bar(s). Cutaneous testing with stainless steel discs supplied by the bar manufacturer does not provide accurate screening for allergy to the implant used in the Nuss procedure.